Axial type reciprocating pump, compressor, motor, and engine



Dec. 8, 1953 J. M. TOWLER ETA AXIAL TYPE L RECIPROCATING PUMP, COMPRESSOR, MOTOR, .AND ENGINE Filed April 8, 1947 3 Sheets-Sheet 1 A Home y Dec. 8, 1953 J. M. TOWLER ET AL AXIAL TYPE RECIPROCATING PUMP, COMPRESSO MOTOR, AND ENGINE 3 Sheets-Sheet 2 Filed April 8, 1947 Dec. 8, 1953 J M TOWLER ETAL 2,661,700

AXIAL TYPE l RECiPROCATING PUMP, COMPRESSOR,

' MOTOR,- AND ENGINE Filed April v8-, 194'7 3 Sheets-Sheet 3 FIG. I0 4 g I I I1 I? J J l6 5 20* o 66 |'6| LB 21 III 5 l6- 6' 7 I IO F IG. 5.

J, Invenlur M BW? W A HuIIley Patented Dec. 8, 1953 UNITED STATES PATENT OFFICE AXIAL TYPE RECIPROCATING PUMP, COM- PRESSOR, MOTOR, AND ENGINE land Application April 8, 1947, Serial No. 740,064

Claims priority, application Great Britain May 3, 1946 19 Claims. (01. 103162) This invention relates to hydraulic multi-ram pumps of the kind having a cylinder block in which the pump rams and associated cylinder bores are disposed around a common axis, the rams being reciprocated either directly or through push rods without the interposition of connecting rods by means of a ram actuating device comprising a wobble plate which is usually in the form of a flat plate or disc and is given angular oscillation in twoplanes in relation to the axis of the rams, such oscillation being produced either by supporting the ram actuating member on a swash member or Z crank hereinafter termed a swash member-the cylinder block in this case being stationaryor by rotating the cylinder block and a ram actuating device each about its own axis, the two axes intereoting at an oblique angle. In this latter case, either the cylinder block or the ram actuating device may be directly coupled to the driving shaft, power being positively transmitted through gearing either from the cylinder block to the ram actuating device or vice versa and in these cases the rain actuating device will be a nonoscillating member. It will be understood that the cylinder block may be in one piece, or it may comprise a. number of cylinder blocks secured together and forming one assembly. It will be further understood that if a pump of this construction is supplied with pressure fluid and provided with suitable valve gear it will operate as a rotary motor, to which this invention may be applied with equal facility and the term pump hereinafter used in this specification is to be read as including a motor.

Reciprocating pumps of the axial type defined above have the great advantage overthe conventional reciprocating ram pump in that they are very compact but so far as we are aware no pump of this type has been evolved which is capable of eflicient operation at the higher pressures customary in modern hydraulic practice, said pressures being anything up to and frequently exceeding 10,009 pounds per square inch.

To obtain continuous operation at these high pressures with comparative absence of wear on the ram ends and the contacted surface of the ram actuating device, it is theoretically essential to have a substantially pure rolling contact between the ram ends and the actuating device.

We have discovered that to obtain this substantially pure rolling contact in practice the following must obtain: (a) the part of the ram actuating device which is contacted by the rams should be given a predetermined rotational dis- 2 placement in relation to the cylinder block by means of toothed gearing serving operatively to connect the actuating device to the cylinder block, the ratio of teeth in said gear connection being equal to or substantially equal to the secant of the angle of the face of the ram actuating device to a plane normal to the axes of the rams; (b) the contacted ends of the rams being free to turn when twisted by the relative motion of the rain actuating device; and (c) the parts should be arranged so that the point of intersection of the axis of rotation of the, ram actuating device and the axis of rotation of the driving shaft and/or cylinder block lies in the same plane as the'iace of the ram actuating device which is contacted by the rams and so that said point of intersection also lies in the pitch plane of the toothed wheel on the cylinder block and coincides with the apex of the pitch cone of the toothed wheel of the ram actuating device.

The ratio between the number of teeth in one wheel to the number of teeth in the other wheel,

of the gear connection is such that in the case of a pump with a stationary pump body the rotational displacement of the ram actuating device is in a reverse direction to the rotation of the swash member. In the case of a pump; with a cylinder block which rotates, the rotational displacement of the ram actuating device would be in the same direction as that of the cylinder block only slightly faster. For example, where the angle between the face of the ram actuating member which contacts the rams and a plane normal to the axes of the rams is 12 degrees, a suitable ratio is 93 teeth on one wheel to 91 teeth on the other wheel.

In the absence of the gear connection of the present invention the obtaining of the required relative motion between the ram ends and the contacted surface of the ram actuating device is completely dependent upon the frictional contact between the ram ends and the ram actuating device and therefore, unless the ram actuating device is mounted upon frictionless bearings, there is the danger that the frictional contact will not be sufficient to ensure relative motion, and, consequently, there-will be skidding between the ram ends and the contacted surface of the ram actuating device. The gear connection of the present invention avoids skidding by providing, positively, the same relative motionbetween the ram ends and the contacted surface of the ram actuating device as would be obtained were the ram actuating device mounted on abso lutely frictionless bearings.

In designing the axial type of pump for operation continuously at high pressures one difficulty met with has been to provide, in the restricted space available, a suitable bearing to withstand the very heavy axial thrusts. Ball or roller bearings have been suggested for this purpose but we are not aware of any ball or roller bearing which is capable of carrying thrust loads of the order required by the very high pressures now normal in hydraulic apparatus. For this reason plain bearings must be used for high pressure work but as such bearings have a very high starting friction the eventual breakdown of the pump through skidding becomes a certainty.

The gear connection of the present invention effectively removes this objection and consequence we are enabled to use plain bearings capable of carrying the highest thrust loads likely to be met with in practice, which affords the added advantage that the size and cost of the pump is considerably less than would be possible with ball or roller bearings. A suitable thrust bearing for a pump according to the present invention is one comprising two plane and relatively rotatable opposed surfaces which are held out of metal to metal contact by an interposed film of oil. If necessary the efiect of surface flexure in such a hearing may be counteracted by making one or both opposed surfaces slightly concave, for example, one-thousandth ofan the center of a diameter of three inches. Alternatively the thrus hearing may be supported on an annular surface having a diameter intermediate the inner and outer diameters of an annular thrust Washer.

With such a bearing we have been able, under test, satisfactorily to operate an axial type reciprocating pump at delivery pressure approaching 15,000 pounds per square inch, and although the surfaces when the hearing was dismounted showed signs of Scratchings due to solid impurities in the oil, its performance was otherwise satisfactory.

We have discovered that if a relative tilt is permitted between the opposing surfaces. in a bearing of the above kind audit the load is eccentric to the axis of the bearing the opposing surfaces will not be operatively parallel but will be forced by the oil film to form between them a space of wedge-like form extending across the opposed r surfaces, said oil film acting to hold the. two surfaces out of metal to metal contact.

In a pump according to the present invention, in its preferred construction, is stationary and the ram actuating member is contacted on one face by rods and is supported on the other face against the axial thrust of the rams by the inolinedface, of the Z crank through an interposed axial thrustv hearing as previously described.

In order that the invention may. be clearly understood and carried into efiect threeembodiments of the same will now be described, by way of example, by aid of the accompanying. draw.- ings in which:

Fig. 1 is a sectional elevation through thepreferredembodiment in which the cylinder block is stationary and arranged with its axis coinci-.

dent with the axis of the driving shaft forv a. rain actuating device which consists of a Z crank or swash member on which is mounted a Wobbler. Fig. 2 is a sectional perspective view of? the pump shown in Fig. 1.

Fig. 3 is a part sectional elevation of a portion of the pump shown in Fig. 1 illustrating the inch at i the cylinder block.

the ram. ends or push.

swash member, Wobbler and gear connection and showing to a greatly exaggerated scale supposedly formed wedge-shaped gaps containing the oil films of the two thrust bearings on both sides of the swash member the gap between the Wobbler and the swash member being indicated by the reference letter A and the other gap on the opposite side of the swash member by the reference letter B.

Fig. 4 is a diagrammatic sectional elevation of an embodiment in which both the cylinder block and ram actuating device revolve and in which the driving shaft is coupled directly to the ram actuating device, the cylinder block being driven from the latter through tooth gear in the form of an inter-meshing crown and bevel wheel.

Fig. 5 is a diagrammatic sectional elevation of an embodiment which is similar in every way to Fig. 4 except that the driving shaft is coupled di- 3 rectly U0 the cylinder block and the rain actuat- 1 face of the ram actuating device showing the paths described thereon by the axis of one of the rams and its point or" contact respectively.

The axial pump illustrated in Figs. 1 and 2 of the drawings comprises a casing l for a motor which is connected by a flexible coupling to: a driving shaft 2 having at its lower end an enlarged boss formed with an oblique lower face 3, the whole constituting the swash member which is referred to generally by the numeral ll. Supported by the oblique face of the swash member is the Wobbler 5. This Wobbler is free to tilt in relation to the oblique face of the swash member and is, for preference, made wholly of hardened steel, or, in the larger sizes, the upper and lower faces thereof are hardened, and around the peripheral edge of the lower faceare cut, or there is otherwise provided, a series of teeth to form a bevel wheel 8 which meshes with a crown wheel I that is secured to orformed integral with the upper face of the cylinder block 8.

The cylinder block 8 in this example is stationary and is bored to provide six or other required number of cylinders 9. These cylinders are arranged symmetrically and at equal distances from each other around the vertical axis of the pump and each is provided with a ground and freely rotatable and reciprocable plunger E9. The inlet and discharge openings and valves for each cylinder are in the example iilustrated arranged in the manner described in our British Patent No. 489,691, that is, each pump ram almost completely fills its bore or cylinder at the end of the discharge stroke whilst the inlet valve 9a is arranged at the inner end co-axial with its bore or cylinder and the delivery outlet 9b in the side wall thereof as close as possible to the lower end of the bore or cylinder. The stem of each inlet valve is suitably guided and a series of inlet passages H are provided, said passages communicating with a chamber 12 common to all of them which chamber is maintained full of oil.

The pump ram ends which bear against the opposing face of the ram actuating member are convex and spherically or conically shaped with the centre of curvature or centre of thrust at,

all times within the cylinder bores so as to en sure, the minimum. offset loading between the pump rams and their bores throughout the delivery or discharge strokes.

To maintain an inlet pressure within the chamber 52 sufficient to hold the pump rams in contact with the Wobbler on their outward stroke there is provided a gear pump or other type of booster pump is and this pump is driven from the main driving shaft 2 by means of an axial secondary shaft [4, the connection between said secondary shaft and the main shaft 45 of the gear pump consisting of a flexible coupling 15c, both said shafts having freedom for axial movement.

Alternatively, instead of employing a flexible coupling which permits the swash member to be free to tilt, the same effect may be attained if the booster pump driving shaft is sufiiciently flexible.

In the example illustrated the rear face of the wobbler bears directly against the oblique face of the swash member and the rear face of the swash member bears directly against the surface of a hardened steel thrust ring to which in turn seats against the underside of the outer ring of a ball or roller bearing journal H.

The use of a single ball or roller bearing jour nal ll, intermediate the length of the shaft 2, in conjunction with a flexible coupling is for the upper end of said shaft or a sufhciently flexible shaft permits the swash member 4 to have limited freedom to tilt sumcient to permit the same either to seat squarely against the thrust ring it or to tilt under the offset load so that the opposing surfaces are then held out of actual metal to metal contact by a wedge-shaped film of oil.

In this construction the swash member may be made of gun metal or it may be made of mild steel faced with white metal. Aiterna tively the surface of the swash member may be hardened steel and the rear face of the Wobbler may be faced with white metal and the surface of the thrust ring also faced with white metal. As far as we have been able to ascertain the soft surface should be the surface in relation to which the load is stationary. In the case of a pump with a stationary pump body the soft surface should rotate.

If desired the thrust bearing between the swash member and the Wobbler may consist of a white metal faced circular mild steel washer which is pinnedto prevent the same from rotating in relation to the swash member.

Radial oil grooves I9 are provided in the faces of the swash member and radial holes 20 are provided in the Wobbler and thrust ring to permit oil to gain access to spaces 2i and 22, the space 2| being between the Wobbler and a pintle 23 on the underside of the swash member on which the Wobbler is mounted so as to be free to rock in relation to the oblique supporting face of the swash member and the other space 22, being between the thrust ring and the driving shaft 2. A continuous supply of oil is thus available at the inner ends of the grooves along which it is propelled by centrifugal action due to the rotation of the shaft. Oil from space 22 is free to circulate through the thrust ring It and ball or roller bearing I! and any excess oil is permitted to escape through the valve controlled outlet 24.

It will be appreciated that the pressure of the oil film will tend to force the opposed surfaces of the thrust bearings apart, and as the intensity of pressure is at a maximum at a part of the perimeter it may cause the surfaces to become con-- vex due to ilexure, and this fiexure may be further accentuated by the high temperature of the opposing surfaces. If the thrust load is small, or if the opposed members are very robust or very rigidly supported, this fiexure may be negligible. On the other hand, if the thrust load is heavy or one of the opposed members is comparatively thin, or inadequately or badly supported, the flexure may be such as to prevent the creation of an effective pressure film of oil between the surfaces, and consequently they will come into contact. In the latter case, in order to counteract the effect of fiexure, one or both of the opposed surfaces may be made slightly concave. For instance with reference to the Wobbler herein described in which the plate is comparatively thin and the load is applied near the centre, we have found it necessary to make the surface opposed to the swash member slightly concave, of the order of one thousandth of an inch at the centre of a diameter of three inches, in order to ensure a high load bearing capacity. In the said embodiment the load is applied near the centre of the Wobbler by the ram ends which make contact with the Wobbler at a radius of less than half that of the radius of the perimeter of the opposed surfaces; and the pressures of the oil film between the opposed surfaces is thought to be at a maximum nearer the perimeter; consequently there is a fiexure of the Wobbler plate due to the pressure and temperature of the oil film and we maize the surface concave to allow for this flexure.

The annular thrust washer it may be supported on an annular surface having a diameter intermediate its inner and outer diameters.

It will be seen therefore that the opposed surfaces are so supported and/or so shaped and the load is so applied that when subject to the pressure and temperature of the oil film created between them at maximum load bearing capacity, they are prevented from coming into contact.

It will be understood that if springs are provided to maintain contact between the ram ends and the surface of the ram actuating member the booster pump may be dispensed with without departing from this invention. Also when the invention is applied to motors or engines it is probable that booster pumps will not be required. because the fluid pressure will maintain the ram ends in contact with the wobble plate.

In the preferred example just described the cylinder block is stationary but it is a simple matter to apply the invention to a design in which the cylinder block is rotated.

The invention is also applicable to that type of axial reciprocating ram pump in which the axis of the driving shaft is at an angle to the common axis of the cylinder block and the face of the ram actuating device is transverse to the axis of the driving shaft.

Examples of both such embodiments are-shown in the accompanying drawings and will now be described.

In Fig. 4 there is illustrated the embodiment in which the driving shaft drives-the actuating device directly, the axis of the driving shaft being at an angle to the common axis of the cylinder block. Also both the cylinder block 8 and the ram actuating device revolve, the driving connection between the two consisting of toothed gear ing as in Fig. 1 in the form of intermeshing bevel and crown wheels 8 and 'I so that the cylinder thei is fi in dim r im e e e .111,

this example, as in the example illustrated in Figs. 1 and 2, the actuating device is supported against thrust by a thrust washer or reaction plate I8 and the said actuating device is also mounted so as to be free to tilt in relation to the thrust Washer.

In the present embodiment rams are employed similarly to the embodiment shown in Figs. 1 and 2, and the convex ends of these rams make direct contact with the opposing face of the actuating device, which in this example is transverse to the axis of its rotation. As there is relative rotational displacement between the actuating device and the cylinder block so the.

ratio between the number of teeth in the two members of the gear connection is equal to or substantially equal to the secant of the angle of the face of the actuating device to a plane normal to the axes of the rams and such that the rotational displacement of the ram actuating device is in the same direction as the rotation of the cylinder block but slightlyfaster.

The embodiment illustrated in Fig. shows the application of the invention to a design in which both the actuating member and the cylinder block revolve the cylinder block being positively or directly driven through the integral or attached shaft 2 and the actuating device being driven by the cylinder block through the intermeshing bevel and crown wheels 6 and 1'. The ratio between the number of teeth in the two gear wheels is the same as in the example shown Fig. 4, so that there is rotational displacement of the actuating member in relation to. the cylinder block so that it rotates in the same direction as the cylinder block but at a faster'rate for the purpose of ensuring substantially a pure rolling contact between the ram ends andthe face of the ram actuating device. The thrust bearing for the actuating device 5 is as in the example shown in Figs. 1, 2 and 3 in that it comprises a thrust ring l6.

In Fig. 6 is shown a portion of a ram actuating device A and on it two curves B and C traced by the point of contact of one of the rams and an imaginary point corresponding to the extended axis of said ram respectively. The two curves are traced simultaneously and the curve B is a parallel to the curve C which is an epicycloid. When the ram is at the middle of its stroke it has a pure rolling contact with the actuating device, the axis of the ram at such times being at one of the cusps D in the curve C. At all times when the ram is not at the middle of its stroke it has a spinning action which varies harmonically, attaining a maximum when the ram is at the end of its stroke. These positions are indicated at E and F on the diagram. This spinning motion is transmitted to the ram, the same being free to turn in its bore, and its amplitude is about one-sixteenth of a revolution.

As will be seen from the drawings in all the examples shown the point of intersection of the axis of rotation of the ram actuating device and the axis of rotation of the driving shaft and/or cylinder block lies in the same plane as the face of the ram actuating device which contacts the rams.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that What we claim is:

l. A hydraulic multi-ram pump comprising,

in combination, a cylinder block which is formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and freely rotatable in said bores, a ram actuating device having a face relatively inclined to a plane normal to said axis and located in opposed operative contact with the outer ends of said rams, means for maintaining said rams against said face, power means for effecting a relative wobbling movement between said block and device about said axis whereby to effect reciprocation of said rams in progressive timed sequence, means for admitting and discharging liquid to and from said bores as said rams are reciprocated, and toothed gearing operatively connecting said actuating device to said block, the tooth ratio of said gearing being such as to eiTect rotational displacement of said device in relation to said block to produce substantially a rolling contact between said face and the contacting ends of said rams,

2. A hydraulic multi-rain pump comprising, in combination, a cylinder block which is formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of freely rotatable rams respectively reciprocable in said bores, each bore having valve controlled inlet and outlet means for the liquid being pumped, a ram actuating device comprising two relatively rotatable parts, one or said parts being a power operable swash plate having a face inclined to a plane normal to said axis and the other of said parts being a Wobbler contacting the outer ends of said rams and being supported by said face against the axial thrust imposed by said rams during the delivery strokes, means for maintaining said ram against said Wobbler, and intermeshing gear elements respectively on said block and Wobbler, the number of teeth of one element being different from the number of teeth of the other element to cause said Wobbler to be rotated positively relatively to said block to an extent such as to cause the contact between said Wobbler and the outer ends of said rams to be made with a substantially pure rolling action.

3. A pump according to claim 1 in which said cylinder block and actuating device are rotatable on relatively inclined axes intersectin at a point substantially in the plane of said face, and said actuating device is adapted for direct power operation and said block is rotatable by said device through said gearing, and in which said gearing has a tooth ratio substantially equal to the secant of the angle of said face to said plane so as to effect slightly faster rotation of said device than of said block.

4. A pump according to claim 1 in which said cylinder block and actuating device are rotatable on relatively inclined axes intersecting at a point substantially in a plane of said face, and said block is adapted for direct power operation and said device is rotatable by said block through said gearing, and in which said gearing has a tooth ratio substantially equal to the secant of the angle of said face to said plane so as to eifect slightly faster rotation of said device than oi said block.

5. A hydraulic multi-ram pump comprising, in combination, a cylinder block: formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality'oframs respectively reciprocable and r satable in said bores, a ram actuating device having a working iace relatively inclined to a plane normal to said axis and located in opposed operative contact with the outer ends of said rams, means for causing said rams to maintain operative contact with said working face, power drive means for efiecting a relative gyratory rocking motion between said face and said block whereby to effect reciprocation of said rams in progressive timedsequence, means operable in timed relation to said motion for admitting and discharging fluid to and-from each of said bores at the inner end of the associated ram as said ram is moved respectively in its outward and inward strokes, and means associated with said power drive means for effecting in positive timed relation to said motion a relative rotational displacement between said face and said block whereby to obtain substantially a rolling contact between said face and the contacting ends of said rams. V H

6. A hydraulic multi-ram pump comprising, in combination, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and rotatable in said bores, a ram actuating device having a generally flat working face relatively inclined to a plane normal to said axis and located in opposed operative contact with the outer ends of said rams, said face having a central axis inclined to and intersecting said first mentioned axis substantially in the plane of said face, the outer contacting ends of said rams being rounded, means for causing said rams to maintain operative contact with said working face, power drive means operative to effect a relative revolving angular oscillation between said face and said plane whereby to effect reciprocation of said rams in progressive timed sequence, and operative also to efiect in positive timed relation to said oscillation a relative rotational displace,- ment about said first mentioned axis between said face and said block whereby to obtain substantially a rolling contact between said face and said contacting ends of said rams, and means operable in timed relation to said reciprocation of said rams for admitting and discharging fluid to and from said bores at the inner ends of said rams.

7. A hydraulic multi-rarn pump compri ing, in combination, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and freely rotatable in said bores, a ram actuating device having a working face relatively inclined at a predeterm ned angle to a plane normal to said axis and located in operative contact with the outer ends of said rams, means for causing said rams to maintain operative contact with said working face, power operable means for effecting a relative gyratory rocking motion between said face and said whereby to eifect reciprocation of said rams in progressive timed sequence, and toothed gearing interconnecting said block and device operable to effect a positive predetermined relative rotational displace ment between said block and device about said axis in timed relation to said oscillation in direction and degree to obtain rolling contact between said face and said ram ends.

8. A hydraulic multi-rarn pump comprising, in combination, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and freely rotatable in said bores, a ram actuating device having a working face relatively inclined at a predetermined angle to a plane normal to said axis and located in operative contact with the outer ends of means for causing said rams to maintain operative contact with said working face, power operable means for effecting a-relative gyratory rocking motion between said face and said rams whereby to effect reciprocation of said rams in progressive timed sequence, a crown wheel fixed on said block and coaxial therewith, a bevel wheel fixed on said device and coaxial therewith and. meshing with said crown wheel, the-tooth ratio of said wheels being substantially equal to the secant of said angle, whereby as an incident to said oscillation a pre determined relative rotational displacement between said bloclr and device is effected, the contacted ends of said rams being free to rotate when twisted by the relative motion of said device, the respective axes of said block and face intersecting at a point which lies in the plane of said face and the pitch plane of said crown wheel and which coincides substantially with the apex of the pitch cone of said bevel wheel.

9. A pump according to claim 1 in which the ratio of the meshing teethof said gearing is substantially equal to the secant of the included angle of said face of said ram actuating device to said plane normal to said central axis.

10. A hydraulic multi-ram pump comprising, in combination, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and rotatable in said bores, a ram actuating device having a working face relatively inclined to a plane normal to said axis and located in opposed operative contact with the outer. ends of said rams, said block: being stationary, means for causing said rams to maintain operative contact with said working face, power operable drive means for actuating said device to impart to said face a gyratory rocking motion and revolving in a predetermined direction about said axis whereby to effect reciprocation of said rams in progressive timed sequence, means operable to effect rotation of said face oppositely to said direction and in positive timed relation to said oscillation whereby to obtain substantially pure rolling contact between said face and said ram ends, and means for admitting and discharging liquid to and from said bores as said rams are reciprocated respectively through their outward and inward strokes.

11. A hydraulic multi-ram pump comprising, in combination, a non-rotatable cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable and being rotatable in said bores and projecting from one end of said block, a ram actuating devicecomprising a wobble plate having a working face disposed at a predetermined angle to a plane normal to said axis and said rams and disposed in operative contact with the outer ends of said rams, said plate having a central axis inclined to and intersecting said first mentioned axis substantially in the plane of said face, means for causing said rams to maintain operative contact with said working face, power operable drive means for actuating said device to impart to said face a gyratory rocking motion and revolving in a predetermined direction about said first mentioned axis whereby to effect reciprocation of said rams in progressive timed sequence, a toothed gear wheel coaxial-and rigid with said cylinder block, a. toothed gear wheel coaxial and rigid with said wobble plate and m'eshingat one side with said. first mentioned wheel so as to roll on said first mentioned wheel in the course of said angular oscillation, the tooth ratio of said gear wheels being substantiallyequal to the seca-nt of said angle whereby to effect rotation of said wobble plate in a direction opposite to said first mentioned direction, and means for admitting and discharging liquid to andfrom said bores as said rams are reciprocated respectively through their outward and inward strokes.

12. A hydraulic multi-ram pump comprisingin combination, a casing, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, and supported in said casing for rotation on said axis, a plurality of rams respectively reciprocable and rotatable in said bores, a ram actuating device supported for rotation in said casing and having a drive shaft for imparting rotation thereto and having an end working face relatively inclined at a predetermined angle to a plane normal to said axis and disposed in opposed operative contact with the outer ends of said rams, said face having a central axis inclined to and intersecting said first mentioned axis at a point substantially in the plane of said face, means for causing said rams to maintain operative contact with said working face, a coaxial toothed gear element rigid with said block, a coaxial toothed gear element rigid with said device and meshing with said first mentioned element, said gear elements being operative by said device to impart rotation to said block, the tooth ratio of said gear elements being substantially equal to the secant of said angle whereby said device is rotatable in the same direction as said block but at a faster speed to produce substantially a pure rolling contact between the ram ends and said face of said device, and means for admitting and discharging liquid to and from said bores as said rams are reciprocated respectively on their outward and inward strokes.

13. A hydraulic multi-ram pump comprising, in combination, a casing, a cylinder block formed with a, plurality of cylinder bores arranged annularly around a central axis, and supported in said casing for rotation on said axis, a plurality of rams respectively reciprocable and rotatable in said bores, a ram actuating device supported for rotation in said casing and having an end working face relatively inclined at a predetermined angle to a plane normal to said axis and disposed in opposed operative contact with the outer ends of said rams, means for causing said rams to maintain operative contact with said working face, a coaxial drive shaft connected to said block, said face having a central axis inclined to and intersecting said first mentioned axis at a point substantially in the plane of said face, a coaxial toothed gear element rigid with said block, a coaxial toothed gear element rigid with said device and meshing with said first mentioned element, said gear elements being operative by said block to impart rotation to said device, the tooth ratio of said gear elements being substantially equal to the secant of said angle whereby said device is rotatable in the same direction as said block but at a faster speed to produce substantially a pure rolling contact between the ram ends and said face of said device, and means for admitting liquid to and from said bores as said rams are reciprocated respectively on their outward and inward strokes.

14. An axial type reciprocating pump according to claim in which said ram actuating device is supported by a thrust bearing in opposition to the axial thrusts of said rams, said bearing comprising reaction parts having two opposed surfaces subject to relative rotation and main tained out of direct contact by an interposed film of oil.

15. An axial type reciprocating pump according to claim 5 in which said ram actuating device comprises a fixed thrust plate, a rotatable swash member having bearing support against said plate, the opposed bearing surface of said plate and member being maintained out of direct contactby an interposed film of oil, a Wobbler plate enacting with the outer ends of said rams and having bearing support ag inst said member and being constrained against rotation with said member, the opposed bearing surfaces of said member and Wobbler plate being maintained out of direct contact by an interposed film or oil.

16. An axial type reciprocating pump according to claim 15 in which said swash member has an axial shaft supported in a journal bearing per mitting relative tilt between said opposed hearing surfaces of said thrust piate and member, and said Wobbler plate has a journal support on said swash member permitting relative tilt between said opposed bearing surfaces of said member and Wobbler plate, tilt out of parallel relation in each instance causing the afiected film of oil to assume a corresponding wedge shape.

1'7. An axial type reciprocating pump according to claim 15 in which oil distributing grooves are provided between said opposed bearing surfaces and oil transfer holes are provided in said thrust plate and Wobbler plate for transferring lubricating oil to the inner ends of said grooves, the oil being free to be propelled outwardly along said grooves by centrifugal action.

18. A hydraulic multi-ram pump comprising,

"'1 in combination, a, cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable in said bores, a r an actating device comprising a member having a working face relatively inclined to a plane normal to said axis and located in opposed direct operative contact with the outer ends of said rams, means for maintaining said rams against said face, power drive means for imparting a gyratory rocking motion to said face relative to block whereby to effect reciprocation or" said rams in progressive timed sequence, and means for admitting and discharging liquid to said bores said rams are reciprocated respectively on their outward and inward strokes, said device being supported by a thrust bearing in opposition to the axial thrusts of said rains, said bearing com prising reaction parts having two opposed hearing surfaces subject to relative rotation and maintained out of direct contact by an interposed film of oil, the bearing surface of one of said reaction parts being normally dished in shape and adapted to assume a substantially flat shape upon flexure of said part resulting from the reaction thereof to the axial thrusts of said rams.

19. A hydraulic multi-rain pump comprising, in combination, a cylinder block formed with a plurality of cylinder bores arranged annularly around a central axis, a plurality of rams respectively reciprocable in said bores, a rain actuating device comprising a member having a working face relatively inclined to a plane normal to said axis and located in opposed direct operative contact with the outer ends of said rams, means for maintaining said rams against said face, power drive means for imparting a gyratory rocking motion to said face relative to said block whereby to effect reciprocation of said rains in progressive timed sequence, and means for admitting and discharging liquid to said bores as said rams are reciprocated respectively on their outward and inward strokes, said last mentioned means comprising inlet valves of the mushroom type opening inwardly into the closed ends of said bores in opposed relation to the inner ends of said rams, said rams at the ends of their discharge strokes substantially filling said bores and extending into closely spaced relation to said valves, said device being supported by a thrust bearing in opposition to the axial thrusts of said rams, said bearing comprising reaction parts having two opposed bearing surfaces subject to relative rotation and maintained out of direct contact by an interposed film of oil.

JOHN MAURICE TOWLER.

FRANK HATHORN TOW'LER.

References Cited in the nle of this patent UNITED STATES PATENTS Number Name Date 225,651 Silver Mar. 16, 1880 Number Number Name Date Silver Jan. 8, 1884 Berry July 15, 1890 Dean Apr. 16, -1 Davis Aug. 6, 1918 Almen Apr. 8, 19 19 Brackett June 24, 1919 Benedek Feb. 25, 1936 Lauret Oct. 4, 1938 Reader June 3, 1941 Gollmer Jan. 5, 1943 MacNeil 1 Dec. 5, 1944 Huber Oct. 2, 1945 Beaman et a1. Jan. 25, 1949 FOREIGN PATENTS Country Date Great Britain 1938 Great Britain 1944 

